ReadableStreamDefaultController prototype methods/getters all fail in with "this" is not a ReadableStreamDefaultController

[colelawrence]

What version of Bun is running?

1.2.1+ce532901c

What platform is your computer?

Darwin 24.3.0 arm64 arm

What steps can reproduce the bug?

I'm not sure exactly how to reproduce this bug, because it occurs when a certain number of conditions are met within the Effect fiber runtime & scheduler.

It occurs in code that looks like this, but I suspect that the reproduction requires certain conditions to come together for the event loop/runtime to cause this.

export const toReadableStreamRuntime = /*#__PURE__*/dual(args => isStream(args[0]), (self, runtime, options) => {
  let i = (++j * 1e6);
  const runFork = Runtime.runFork(runtime);
  let currentResolve = undefined;
  let fiber = undefined;
  const latch = Effect.unsafeMakeLatch(false);
  return new ReadableStream({
    start(controller) {
      const id = `READABLE-${++i}`;
      fiber = runFork(runForEachChunk(self, chunk => latch.whenOpen(Effect.sync(() => {
        try {
          console.log(id, "unsafe close");
          latch.unsafeClose();
          for (const item of chunk) {
            console.log(id, "enqueue", item);
            controller.enqueue(item);
          }
          console.log(id, "enqueue done");
          currentResolve();
          console.log(id, "resolve done");
          currentResolve = undefined;
        } catch (error) {
          console.log(id, "error", error);
          throw error;
        }
      }))));
      fiber.addObserver(exit => {
        if (exit._tag === "Failure") {
          try {
            controller.error(Cause.squash(exit.cause));
          } catch (error) {
            debugger
            throw error;
          }
        } else {
          controller.close();
        }
      });
    },
    pull() {
      return new Promise(resolve => {
        currentResolve = resolve;
        Effect.runSync(latch.open);
      });
    },
    cancel() {
      if (!fiber) return;
      return Effect.runPromise(Effect.asVoid(Fiber.interrupt(fiber)));
    }
  }, options?.strategy);
});

What is the expected behavior?

Should be able to access all the getters/functions on ReadableStreamDefaultController

What do you see instead?

Additional information

Related to Effect-TS/effect#4538